Commission, and the Oak Ridge and Los Alamos Laboratories, are contributing to such a study, The data in Japan will be evaluated to determine whether information on persons exposed, their locations at the time of exposure, and shielding effects are adequately known to plan a continental test series which would establish more exactly the amounts of radiation received by the Japanese, Study of Radon Concentrations 14, To learn more about safe radon concentrations in uranium mining, three AEC representatives recently visited the gold mines in Johannesburg, Union of South Africa, and the uranium mine of the Union Miniere de Haut Katanga in the Belgian Congo, 15, Several features make the South African mines particularly useful in studying the effects of radon, At the present time the total population of workers in the South African uranium mines is approximately 270,000, This is possibly the largest single group of individuals in the world with common radiation expcsure. Also important are the excellent medical control procedures and records maintained in this area, * DOE ARCHIVES 16; It was determined by the AEC representatives that the concentrations of radon in a number of gold mines were in the range of our concurrently accepted maximum permissible concentration and that there appeared to be no unusu2l incidence of lung cancer in the mining population, ne Government of the Union of South Africa was strongly urged to amplify these preliminary studies and to carry them to completion since it would contritute greatly to our confidence in the accepted safe level of exposure to radon,

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